Nose fuzes of the percussion type including a self-destruction device



May 8, 1962 w. GUERNE NosE FUZES OF THE PERCUSSION TYPE INCLUDING A SELF-DESTRUCTION DEVICE Filed June 3, 1959 2 Sheets-Sheet 1 INVEN TOR WILLIAM G'LIERNE $2 .3 1 DQ9ZO4XITORNEY y 8, 1962 w. GUERNE 3,033,115

NOSE FUZES OF THE PERCUSSION TYPE INCLUDING A SELF-DESTRUCTION DEVICE Filed June 5, 1959 2 Sheets-Sheet 2 NVE N TOR WILLIAM GUERNE m V 'VWTORNER il-lit:

The present invention relates to percussion fuzes including a self-destruction device intended to be mounted at the front end of the nose of a rotating projectile. In the present description, the term firing pin or firing member will be taken in a very general meaning and will include any part, movably axially and capable, by its rearward displacement'produced by an impact, of causing the operation of the primer of the fuze, whether this primer is operable by a mechanical shock or by an electric contact. The operation is more especially concerned with fuzes for small caliber explosive shells.

The object of the present invention is to provide a fuze of the above mentioned type which is better adapted to meet the requirements of practice, and in particular which has a more reliable operation in case of oblique impact upon a target. i a a The fuzes with which the invention is concerned include aself-destruction mechanical device, of the known type, including an axially slidable unit which is urged in the. rearward direction by suitable spring means to bring it into a rear position where it causes operation of the fuze but which is held in a front position against the action of said spring means by centrifugal weights cooperating with inclined surfaces as long as the speed of revolution of the projectile is at least equal to a predetermined value. When said speed of revolution drops below said value, the thrust of the spring overcomes the effect of the centrifugal force on said weights and causes said unit to be moved into said rear position. According to the present invention, there is provided, ahead of said sliding unit, in a recess, closed at the front, provided in the nose of the fuze body, an abutment against which the centrifugal weights apply said sliding unit as long as the speed of revolution of the projectile remains higher than said predetermined value, this abutment being capable, under the effect of impact upon a target and of the deformation, even very small, of said nose caused by this impact, of throwing said sliding unit toward its rear position in such manner that the centrifugal weights are retracted and percussion can take place.

A preferred embodiment of the present invention will be hereinafter described with the reference to the accompanying drawing, given merely by way of example and in which:

FIGS. 1 and 2 are axial sectional views of two percussion fuzes, respectively, made according to the invention.

The fuz'e includes a body, for instance of a light metal, in which is mounted a self-destruction device including a sliding unit 1 which is urged by a percussion spring 2 toward a rear position in which operation of the fuze takes place. Centrifugal weights 3, cooperating with an inclined surface 4, hold said unit 1 in the forward position as long as the speed of revolution of the projectile remains above a predetermined value. When said speed drops below said value, the thrust of spring 2 overcomes the action of the centrifugal force and unit 1 is thrust rearwardly by spring 2 so as to cause the fuze to operate.

In the embodiment shown by the drawing, the firing pin 5 is directly carried by sliding unit 1, and is in fact integral therewith. The front portion of unit 1 is provided with radial housings for balls 3 (which constitute the centrifugal weights) cooperating with an annular frusto-conical surface 4 fixed with respect to the fuze body, spring 2 urging the firing pin toward the rear position where it strikes primer 6. In order to prevent the fuze from operating before it has travelled a sufiicient distance from the gun from which it is fired, any suitable means may be provided. For instance, the sliding unit 1 is prevented from moving rearwardly, before firing and until it has travelled a given distance along its trajectory, by a split ring 7, this ring being surrounded by a thin tin ribbon 8, spiral-wound about it and which is unwound only after the shot has been fired, so as then to permit ring 7 to open under the effect of the centrifugal force, after which the firing pin is retained only by the cooperation of balls 3 with inclined surface 4.

Such a structure is known in the art, and in prior fuzes it was completed by a firing pin head located behind the nose of the fuze body. This head was struck against the target when an impact took place and was pushed rearwardly, thus driving the firing pin toward the primer.

Now, according to the present invention, there is no firing pin head proper and there is provided in a recess,

closed at the front, provided in the nose of the fuze body, an abutment 10 against which balls 3 apply said sliding 'unit, against the action of spring 2, as long asthe speed of revolution of the projectile remains higher than said predetermined value, this abutment being capable, under fthe effect of impact upon the target and of the resulting deformation of said nose, of throwing said sliding unit 1 toward the rear, thus causing balls 3 to be retracted.

According to a first embodiment of the invention illustrated by FIG. 1, abutment 10 is disposed directly ahead of the sliding unit 1. Accordingly, before the shot is fired, said abutment 10 is located at a small distance (A approximately equal to 0.5 mm. for instance) from the front face of unit 1 (which carries balls 3). Once the shot is fired, the centrifugal force acting upon balls 3 causes unit 1 to move forwardly, against the action of spring 2, until it comes into contact with abutment 10 (A being then reduced to zero) without balls 3 having yet come into contact with a radial abutment.

According to a second embodiment of the invention, illustrated by FIG. 2, there is interposed, between sliding unit 1 and abutment 10, a block 11, for instance of brass, slidable axially with respect of the fuze body on the inside of a recess 9, also closed at the front, provided in the nose of the fuze. Advantageously, as shown, the front end of spring 2 bears against said member 11. Thus, when the projectile strikes a target, under the effect of the impact and of the resulting deformation of the nose of the fuze body, member 11 is thrust rearwardly against sliding unit 1 and throws it in the rearward direction while causing centrifugal balls 3 to be retracted.

Advantageously, member 11 is of cylindrical shape and is provided with a blind hole, turned toward the rear and in which the front end of spring 2 is engaged. Member 11 is housed in a cylindrical recess provided in the nose of the fuze, in which it is freely slidable. In this case also, preferably, after assembly of the parts of the fuze but before the shot is fired, the rear face of member 11 (which member is in contact at the front with the abutment surface 10 provided, ahead of said member, in the recess 9 where it is freely slidable) is at a small distance (A being for instance approximately equal to 0.5 mm.) from the front face of unit 1. Once the shot has been fired, A is reduced to zero by the action of balls submitted to the centrifugal force.

When the projectile strikes a target even at a very small angle, the deformation of the nose of the fuze body thrusts member 11 rearwardly so that the ballsare retracted and firing pin 5 strikes the primer.

Such a fuze has a high sensitivity, even in the case of impacts taking place at very small angles, on any kind of target. The transmission to member 11 of the axial component of the forces due to the impact shock, takes place practically instantaneously, even before the nose of the fuze body has had time to undergo a substantial deformation, so that the operation of the fuze remains correct, even if the nose of the fuze body is more or less crushed.

Spring 2, instead of having its front end applied against member 11, might pass through said member and be applied against the front wall of the recess 10 of the fuze body.

In a general manner, while I have, in the above description, disclosed what I deem to be a practical and efficient embodiment of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. A nose fuze for a rotating projectile comprising a nose fuze casing closed at the front, means within said casing forming an abutment face at the inner front end of said casing, a firing member inside said casing disposed to slide longitudinally within said casing between forward and rear positions and having front and rear ends, said front end being formed for abutment against said abutment face when said firing member is in its forward position, primer means for firing the fuze disposed in a'fixed position behind said firing member for contact therewith when said firing member reaches its rear position, with a primer firing element carried at the rear end of said firing member, resilient means biased longitudinally in said casing resiliently urging said firing member to slide to its rear position and centrifugally actuated means comprising movable weights cooperating between fixed surfaces inside said casing and said firing member to urge said firing member to its forward position, the front end of said casing forming a continuous solid wall in front of said firing member and in front of said abutment face capable of preventing direct contact between said firing member and a target struck by said fuze.

2. The nose fuze of claim 1 further comprising means engaging said firing member within said casing for retaining said firing member in an intermediate position between its forward and rear positions before said nose fuze is armed.

3. The nose fuze of claim 1 in which said means forming an abutment face comprises a block disposed forward of said firing member inside said casing and slidable axially in said casing between the inner front portion of said casing wall and said firing member, the rear face of said block being said abutment face, and in which said resilient means comprises a spring compressed axially between said firing member and said block.

References Cited'in the file of this patent UNITED STATES PATENTS 2,405,653 Honger Aug. 13, 1946 2,493,278 Weiss Jan. 3, 1950 2,650,541 Rosselet Sept. 1, 1953 2,790,390 Baker Apr. 30, 1957 2,806,427 Hager Sept. 17, 1957 2,871,788 Guerne Feb. 3, 1959 FOREIGN PATENTS 131,063 Great Britain Aug. 21, 1919 21,046 Finland May 15, 1946 542,742 Italy May 3, 1956 

